The invention relates to a road block which is mounted at the rear end of a road vehicle and comprises a vertical warning panel for protecting a site of road works, and a crash attenuator, the latter being tiltable about a transversal axis from a horizontal operative position into vertical rest position suited for transportation, whereas the warning panel can be moved substantially in a translational motion between an upper operational position and a lower rest position.
The protection of temporary work sites, notably on highways, requires crash attenuators which can be mounted at the rear end of road work vehicles. A warning panel is mounted above and in front of the attenuator and is generally provided with pulsating light signals such as arrows.
Crash attenuators which absorb the crash energy and are susceptible to protect both vehicles and their occupants against severe damages are well known, e.g. from European Patent 0 674 052 or U.S. Pat. No. 4,190,275.
Road blocks according to the preamble part of the annexed claim 1 are well known and in daily use on German highways. Their crash attenuators should be rather long in order the provide a sufficient deceleration path. On the other hand, the length is limited by the tolerable charge supported at the rear side of the vehicle and by the necessity to transport the attenuator in an upright position.
The tilting movement of the attenuator requires powerful electrical or hydraulic motors. The warning panel which in most cases is as large as the vehicle must be accurately guided during its translational movement in order to avoid canting. This requirement results in two synchronous driving means on both sides of the warning panel. Moreover, the transition between the operational and the rest position and vice versa requires a plurality of manipulations which in an emergency case consume too much time. Finally, if the motors fail to operate, several persons are necessary to move the road block from one into the other position.
Therefore, the invention aims to improve a road block of the above defined type by reducing the number of motor means and their driving power and allowing operation by only one person even if the motors fail to operate.
This aim is achieved by the road block which is mounted at the rear end of a road vehicle and comprises a vertical warning panel for protecting a site of road works, and a crash attenuator, the latter being tiltable about a transversal axis from a horizontal operative position into a vertical rest position suited for transportation, whereas the warning panel can be moved substantially in a translational motion between guidance means from an upper operational position to a lower rest position, wherein the tilting movement of the attenuator is coupled to the translational movement of the warning panel via cables or chains in such a way that the attenuator and the warning panels move synchronously to the rest or operational position.
Preferred embodiments of the invention are defined in the secondary claims.